Mobile telecommunications devices, such as smart-phones and laptops, commonly have the ability to participate in a cellular telecommunications network typified by high-power/long distance communications networks over licensed spectrum, and alternatively over low-power/short distance communications networks, over unlicensed spectrum, such as a wireless point-to-point communications network. A typical example is a smart-phone that has a data connection over a 3G or 4G cellular plan, but at the same time may participate on a wireless point-to-point communications network (e.g., a Wireless Fidelity (Wi-Fi) (IEEE 802.11) network and/or a Bluetooth (IEEE 802) network).
A choice between a cellular telecommunications and wireless point-to-point communications network provides a mobile telecommunications device with a corresponding choice for voice communications. For example, a smart-phone may use voice communications over a cellular network or alternatively over a Wi-Fi network via Voice over Internet Protocol (“VoIP”). This is sometimes called Wi-Fi calling (“WFC”).
A user may desire to utilize a wireless point-to-point communications network for conducting voice communications for a number of reasons. For example, the user may be at a location where quality of service over a cellular telecommunications network is not as good or reliable as service over a wireless point-to-point communications network. As another example, the user may determine that conducting voice communications over a wireless point-to-point communications network may cost less that conducting the same voice communications over a cellular telecommunications network, e.g., long distance calling charges may be cheaper via WFC than over a cellular telecommunications network.
However, the ability to access emergency services by dialing 911 is a vital component of public safety and emergency preparedness. The Federal Communications Commission (FCC) has established a set of rules and regulations that require interconnected VoIP service providers to deliver enhanced emergency (E911) services to their subscribers. Interconnected VoIP service providers connect the IP realm and the Public Switched Telephone Network (PSTN), allowing subscribers to benefit from increased efficiency by routing calls over the internet.